Underlayment can serve as a relatively simple fix to an uneven-subfloor. Keep in mind that in some circumstances you won't be able to use underlayment as underlayment should only be used for minor imperfections.
While laminate tends to be more forgiving of subfloor imperfections compared to other types of flooring, it is still important to level your flooring to avoid future damage if you are installing laminate flooring on an uneven subfloor. A level subfloor ensures a more attractive and long-lasting finish.
If you have an uneven sub surface, a underlay floor can potentially help level it out, but we don't recommend this at all. An uneven surface under a floor can cause boards to sink and shift, potentially cracking or splitting them.
This is because the underlay will simply follow the shape of the subfloor which is not flat. Furthermore, laying more than one underlay will reduce the stability of the subfloor and cause more issues than they fix. Ultimately, levelling a subfloor with underlay will do nothing but cost you an extra few dollars.
Ramp option for joining a carpet to a hard floor.
Another floor transition for uneven floors is the Compression Ramp. It is designed to join a carpet to a hard floorcovering, where there is a height difference of up to 5mm either way.
Extra Padding Poses a Risk
By adding unnecessary cushioning, you could actually be causing more harm to your floor than good. The added friction could cause the underlayment to wear down quickly and make your floors less stable over time, causing stress on the floating floor's locking system joints.
Room humidity can vary according to the season, so it is vital that the floor is able to expand and contract. For this reason, make sure you leave an expansion gap on all sides of the floor, around pipes, thresholds and under doors.
If mixed to the correct consistency, self leveling underlayment will spread out when poured onto a surface and seek its own level, lessening the labor required for a very thin coat. If the material is mixed too densely, it will not flow easily and will usually require additional troweling.
We would recommend an underlay of 3 – 5mm for laminate flooring. It should be at least 3mm thick to provide comfort and ground levelling properties. But, it should be no more than 5mm thick. If it's any thicker, you could experience problems with the laminate's locking system.
Underlayment is not optional. If your laminate planks don't have it already attached, we recommend that you buy rolls of underlayment on which to install your laminate floor.
Without underlayment to add a layer between these damp subfloors and the surface flooring, your laminate can quickly become wet, warped, and mildewy, harming its overall integrity. Moisture over time can also break down floor adhesive which causes the floor to start warping.
Underlay thickness affects the feel of the carpet. A thick underlay, between 11 and 12mm, will give your carpet a cushioned, soft feel. However, a thinner underlay on the stairs may be easier to install. 9mm is ideal.
If you've opted for a thinner carpet, you may want to choose a slightly thicker underlay. Popular manufacturers make underlay of around 11mm-12mm and this is ideal. Although for more difficult areas like stairs, a 9mm underlay would be far easier to fit, rather than something as much as 12mm.
Fit Thicker Underlay in Rooms with High Footfall
Rooms with a higher footfall will require a thicker undelay. A thicker underlay will provide a more comfortable feel under the foot and will also be more resilient when it comes to handling the weight and stresses that come with constant traffic.
When laying laminate flooring it is essential that you leave at least a 10-12mm expansion gap around the perimeter of the floor. There are important reasons to do so, and we will cover them in this article. However, you won't need to worry about any spaces around the perimeter of your installation.
You absolutely cannot use carpet underlayment underneath laminate flooring. As much as you want to cut down costs on a new floor, this is not the way to do it. Installing laminate flooring over carpet underlayment will do more harm than good in the long run.
With laminate floors, we typically recommend using rug pads that are made of natural rubber or felt material.
Laminate flooring is very thin, so any unevenness on the subfloor will eventually begin to show as the floor settles into position – you can find out more about this in our 'What is laminate flooring' guide. The spongy effect can be caused by a dip in the subfloor causing an air gap underneath the laminate flooring.
In some cases, a slight slope may be normal and not cause for concern. However, if the slope is severe or getting worse over time, it could be a sign of a serious problem that requires immediate attention. One potential risk of sloping floors is damage to the structural integrity of the home.
Uneven floors in a house are usually a sign of a foundation problem, but not always.